| Tournament details | |
|---|---|
| Year | 2021 |
| Trophy | J. J. Nestor Cup |
| Winners | |
| Champions | Mayo (48th win) |
| Manager | James Horan |
| Captain | Aidan O'Shea |
| Runners-up | |
| Runners-up | Galway |
| Manager | Pádraic Joyce |
| Captain | Shane Walsh |
| Other | |
| Matches played | 4 |
The 2021 Connacht Senior Football Championship was the 2021 iteration of the Connacht Senior Football Championship organised by Connacht GAA.